Help with banner/header overlap

Hi,

I’m fairly new to WordPress and learning along the way. I am using the Longevity theme and when I activate the banner (with an image) on the front page, it looks great, however I want to keep the banner for a all other pages, but without an image. When I do so, the banner seems to be pushed up and covers part of the tagline. Additionally, when I attempt to hover over child menu items (such as About or Services), I cannot access them.

Can someone please help me solve this problem?

Thanks.
Ivana